In a disposable diaper of pants-type, the right and left side edges of front body and the right and left side edges of back body are jointed, a pair of right and left side leg openings and a waist opening are formed on an overall sheet, and an absorbent element, which includes a flexible absorbent disposed between a liquid-pervious top sheet and a liquid-impervious back sheet, is attached to the inner surface of overall sheet, and the absorbent element is placed longitudinally from the front body to the back body within the central portion of overall sheet in the crosswise direction of diaper. Such disposable diapers are used universally.
In general, a disposable diaper of this kind is provided with waist stretchable members comprising rubber threads within a waist area in the front and back bodies along the waist opening's edge. An absorbent core is not located in the waist area. The waist stretchable members are spaced each other in the lengthwise direction so as to be parallel to the waist opening's edges. Another disposable diaper is available in the market, which is provided with girth stretchable members comprising rubber threads and fixed to the girth area which covers from the pair of leg openings to the crotch. An absorbent core is located in the girth area. The girth stretchable members are spaced each other in the lengthwise direction so as to be parallel to the waist opening's edges and placed so as to extend across the absorbent core. The girth stretchable member serves, together with the waist stretchable member, to prevent the diaper from slipping down. In addition, the girth stretchable member serves per se to improve tight contact between the diaper and the wearer's skin.
Particularly, in the disposable diaper of pants-type, the girth stretchable member is constituted of one or more under-waist stretchable members fixed to an underbelly corresponding area in the front body and one or more buttock stretchable members fixed to a buttock area in the back body. This buttock area is correlating to that under-waist area in configuration under-waist area. The under-waist stretchable members and buttock stretchable members are extended continuously from one side edge to the other side edge along the waist circumference fastening direction.
On the other hand, in a disposable diaper with tape-tab fastening means, so-called a disposable diaper of tape-type, the right and left side edges of front body and the right and left side edges of back body are not jointed until the diaper is used (worn) and in general, the above girth stretchable member is not provided.
It has been considered that by fixing the girth stretchable member to the diaper in the conventional way, since the gap formed between an absorbent main body and the wearer's body can be small, the garment fit of diaper to the wearer's skin should be improved so that efficient protection against the leakage can be obtained. However, it is found that since this girth stretchable member is placed so as to extend across the absorbent, the absorbent main body is shirred so as to form longitudinal creases along the direction of the front-back of the product. Then, liquid body exudates like urine is introduced through these creases toward the waist area before being absorbed, resulting in the fear of increased leakage from the front and back areas. Particularly, an infant often takes a pose of getting on all fours and the urine is discharged towards the front side of diaper. Accordingly, a far larger amount of body exudates is introduced to the waist area and leaked in the front body than in the back body.
The conventional girth stretchable member is placed so as to extend continuously along the girth in the front body and along the girth in the back body, respectively. Accordingly, the diaper is shirred so as to form a large number of creases on the whole of girth area, which results in a bad appearance of diaper. Particularly, it is found that since the conventional stretchable member is fixed to the whole of girth area including the area where the absorbent is located, the diaper may have an extremely bad appearance.
Additionally, if visible design such as pattern of animation character is provided on the front and back bodies of diaper, it may not show clearly due to the creases.
In order to solve these problems, it is easiest and effective not to provide girth stretchable members. However, by doing so, the diaper may not exhibit the above effects attained by the girth stretchable member. That is to say, the diaper may slip down and the tight contact between the diaper and the wearer's skin may not be kept sufficiently.